The present invention generally relates to apparatus and methods for optimizing electric machines and, more specifically, to apparatus and methods of using Six Sigma theory for selecting and optimizing high performance electric drives.
Electric machines (EMs) for high performance electric drives (HPEDs) play a significant role in the modern aerospace and military industries. This is particularly true in the area of more electric architecture (MEA) for aircraft, spacecraft, and military ground vehicles. The commercial aircraft business is moving toward no-bleed air environmental control systems (ECS), variable-frequency (VF) and direct current (DC) power distribution buses, and electrical actuation. Some military aircraft already utilize MEA for both primary and secondary flight control. Military ground vehicles have migrated toward hybrid electric technology, where the main propulsion is performed by electric drives. Future space vehicles will require electric drives for thrust vector and flight control actuation. These systems must be more robust and will offer greatly reduced operating costs and safety compared to the existing Space Shuttle hardware. Therefore, substantial demand for improved electric drive performance has arisen.
These new aerospace trends have created a significant challenge for HPED systems, including increased operating voltages, and reduced system losses, weight, and volume. A new set of power quality and EMI requirements has been created to satisfy both quality and performance issues. The overall result is a significant increase in the installed EM, creating challenges for utilizing this equipment on the new platforms. Therefore, overall system performance improvement and power density increase are necessary attributes for the new-generation machines. Cost is an additional driver that must be addressed to make the new platforms affordable.
The process of designing EM to achieve these new requirements requires the selection, analysis and optimization of a large number of characteristics. The complexities of the design process may take a large amount of time and effort and may still not result in an optimal design. As can be seen, there is a need for improving the EM design process to meet the increasing demands of new HPED systems.